Heat exchange apparatus made of sheet metal



, Aug- 1935- c. F. ROSENBLAD 2,011,201

HEAT EXCHANGE AP PARATUS MADE OF SHEET METAL Filed May 2, 1934 Patented Aug. 13, 1935 PATENT OFFICE HEAT EXCHANGE APPARATUS MADE OF SHEET METAL Curt Fredrik Rosenblad, -Sodertalje, Sweden, as-

signor to Aktiebolaget Bosenblads Patenter,

Sodcrtalje, Sweden Application May 2, 1934, Serial No. 723,553 In Sweden May 12, 1933 15 Claims. (01. 257-245) This invention refers to heat-exchange apparatus having their heat transmitting surfaces made of sheet metal (metal plates) bent to a spiral shape to form channels for the media between which heat is to be exchanged. In some cases, for instance, if one or both of said flowing media tend to form precipitates or lncrustations on the heat transmitting surfaces, it is essential that the spiral channels or some of themare not permanently closed at the plane ends (or short sides) of the apparatus but on the contrary may be opened for inspecting and cleans-' ing the heat transmitting surfaces.

Heretofore such open channels in heat exchangers were closed by means of plane lids-or bottoms placed at the ends of the heat exchanger, and plane packings or ribbon-like sealing strips of rubber or other resilient material were' exchange than in permanently closed apparatus.

of the same size and capacity.

When such bottom is used in combination with a plane packing, the fluids or media may leak between the different channels though such deflciency cannot be detected from the outside. If ribbon-like sealing strips are used in combination with draining channels in the plane bottom, it is possible to detect such leakage from the outside but the fault cannot be localized.

The chief object of this invention is to over.- come such drawbacks by means of a device which may be used in combination with the known sealing strips, if desired, and is adapted to close and seal such open channels in spiral sheet-metal heat exchangers. Another object of this invention is that said device shall simultaneously term a support for the edges of the spiral metal sheets, thus rendering it possible to use a lighter construction and thinner sheet metal for the apparatus. Particularly when the apparatus are built of stainless steel, such reduction of the thickness of themetal sheets means a considerable reduction of the price. In addition, the capacity of heat transmission is improved, as the thickness of the sheet metal walls is reduced.

Another object of this invention is to render it possible to detect and to localize, from the outside, any deficiencies of the sealing as may occur in such spiral apparatus.

Another object of this invention is to render it possible to close one or. more of the spiral channels in such heat-exchangers, while simultaneously leaving the remaining channel or channels open, which is in some cases desired. 5

Another object of this invention is to render it possible to construct and operate such spiral heat-exchangers with a minimum of distance pieces and other devices for keeping the widths of the channels constant and staying the apparatus.

Other objects of this invention will be evident from the following description and claims.

The device inaccordance with this invention is'substantially characterized in this that one 15 or more bands or bars, which are bent to spirals and have, for instance, a round, half-round, rectangular or wedge-shaped cross-section, form one or more detachable closers (lids or bottoms) which may be used in combination with known packings, if desired, and are adapted to close one or more of the spiral channels at the ends or short sides of the apparatus.

Some embodiments of the invention are shown in the annexed drawing. 25

Fig. 1 shows a longitudinal section on the line II in Fig. 2 through a heat-exchanger having a closing device in accordance with this invention. Fig. 2 is an end view of the same device. Fig. 3 shows a detail of Fig. 1, on a'larger scale. Fig. 4 shows a modified detail on a larger scale. Fig. 5 shows an axial section through an apparatus having a modified closer in accordance with this invention. Fig. 6 shows one of said closers detached from the apparatus.

Referring now to'Flgs. 1-3 of the drawing, the heat-exchanger shown therein consists of two sheet metal plates l and 2, bent to spirals. Between them there are spiral channels 3, 4 for the heat-exchanging media. (Cf. U. S. Patent No. 1,930,879).

At the ends or short sides of the apparatus metal strips or bars 9l2, with a rectangular cross-section having the edges bevelled towards the channels, are inserted between the plates.

Said strips 9l2 may, preferably, be'wound or rolled simultaneously with the winding of the spiral metal sheets I, 2. During the rolling procedure the outer ends of the strips project from the end sides of the spirals (Figs. 1 and 3). Thereafterthe spiral strips 9-!2 are secured, for instance, by welding to a number of crossbars or spokes l4, preferably of flat iron, which are then by means of bolts I 5 secured to brackets It or the like on the apparatus to absorb the axial pressure from the media within the apparatus. To secure I a perfect sealing, sealing strips ll of rubber, leather or other resilient material are inserted into the channels 3, 4.

The spiral strips 9| 2 together with the spokes I 4 constitute a closer or lid at both ends of the apparatus, in accordance with this invention.

It is, however, also possible to interconnect the windings of the spiral strips by means of welding or the like. The closer may also consist of a loose spiral (without interconnections between its windings) which is kept in position during the operation by means of a loose holder, such as a cross of bars or the like, secured to the heatexchanger when the latter -is in operation.

Such closer is very efficient and simultaneously inexpensive, particularly because it is simple to manufacture, no working of surfaces being necessary. The parts will fit snugly to each other without such working.

In small apparatus, it is suflicient to stay and stabilize the apparatus, by means of said closers and a strip 13 rolled in between the metal sheets centrally, said closers and strip suflicing to keep the metal sheets at a correct distance from each other.

In the embodiment shown in Fig. 4, the channels are alternately open and closed at each end of the apparatus, i. e. the channel closed at one end is open at the opposite end, and reversely. In manufacturing such apparatus, the channel 3 may be closed (at one end of the apparatus) by means of metal strips l9 welded to the metal sheets. The channel 4 is then (at the same end of the apparatus) closed by means of detachable metal strips III, which may be held by spokes 14 or the like, as described above, to form a spiral closer or bottom.

The number of parallel channels to be closed by such spiral closers is arbitrary.

The invention is especially advantageous for cross-current condensers of spiral metal sheets. (Cf. my U. S. Patent No. 1,956,133). An embodiment of such condenser is shown in Figs. 5 and 6. In the channels 3 the cooling medium (such as cooling. water) flows and the channels 4 are to receive the steam to be condensed. The cooling liquid enters through tube 5a and is drawn off through .tube 6a, while the steam, is let in .throu'gh' pipe 1a and the condensate drawn off through tube 8a. The channels 4 are open to the two ends of the apparatus. One of said ends is enclosed by pipe 1a and the other by a bottom 20. The liquid channel 3 is at both ends sealed by rubber strips ll kept in position by metal strips Ill (Fig. 6) rolled to spirals and secured to arms or spokes 14 which are fixed by means of bolts IS. The strips "together with their spokes l4, which are preferably made of edgewise arranged flat iron bars, form together a removable closing device for the channel 3, in accordance with this invention. In such condensers the steam flows in cross-current to (at right angles to) the flowing water.

Said closing device of spiral strips, which may be combined with a suitable sealing of resilient ribbons, efliciently closes the channels 3 for the cooling medium but does not substantially prevent the cross-wise flow through channels 4. All the channels may easily be made accessible for inspection and cleaning.

Certain modifications may be made in the devices shown and described without exceeding the scope of this invention. Thus, the cross-section of the spiral strip may be rectangular, wedgeshaped, square, round, half-round, oval, etc. Preferably, the metal strip is secured to the spokes by weldin though rivets, screws or the like may be used for that purpose. The spokes may be omitted. For them plates or the like may be substituted.

What I claim is:

1. In a heat-exchanger, in combination, heat transmitting sheet metal bent to a spiral shape to form spiral channels for the heat-exchanging media, and at least one removable metal strip bent to a corresponding spiral shape adapted to close one of said channels at the edges of the spiral which are substantially at right angles to the axis thereof.

2. In a heat-exchanger, in combination, heat transmitting sheet metal bent to a spiral shape to form spiral channels for the heat-exchanging media, a packing at the edges of the spiral which are at right angles to the axis thereof, and a metal strip bent to a spiral shape adapted to press said packing against the edges of said heat transmitting surfaces to seal one of said channels.

3. In a heat-exchanger, in combination, heat transmitting sheet metal bent to a spiral shape to form spiral channels for the heat-exchanging media, and removable metal strips bent to acorresponding spiral shape adapted to close said channels at the edges of the spiral which are at right angles to the axis thereof.

4. In a heat-exchanger, in combination, heat transmitting sheet metal bent to a spiral shape to form spiral channels for the heat-exchanging media, removable spiral sealing strips of a resilient material at the edges of said spiral, which are substantially at right angles to the axis thereof, and metal strips bent to a corresponding spiral shape adapted to press said resilient sealing strips into the ends of said channels to close them.

5. In a heat-exchanger, in combination, heat transmitting sheet metal bent to a spiral shape to form spiral channels for the heat-exchanging media, and at least one metal strip bent to a corresponding spiral shape adapted to close one of said channels at the edges of the spiral which are substantially at right angles to the axis thereof, said metal strip having a cross-section tapering towards said edges.

6. In a heat-exchanger, in combination, heat transmitting sheet metal bent to a spiral shape to form spiral channels for the heat-exchanging media, and at least one metal strip bent to a corresponding spiral shape adapted to close one of said channels at the edges of the spiral which are substantially at right angles to the axis thereof, said metal strip having a rectangular cross-section whose edges facing the apparatus are bevelled.

'7. In a heat-exchanger, in combination, heat transmitting-sheet metal bent to a spiral shape to form spiral channels for the heat-exchanging media, and at least one metal strip bent to a corresponding spiral shape adapted to close one of said channels at the edges of the spiral whichare substantially at right angles to the axis thereof, the windings of said spiral metal strip being interconnected.

8. In a heat-exchanger, in combination, heat transmitting sheet metal bent to a spiral shape to form spiral channels for the heat-exchanging media, and at least one metal strip bent to a corresponding spiral shape adapted to close one of said channels at the edges of the spiral which are substantially at right angles to the axis thereof.

the-windings of said spiral metal strip being interconnected by a rigid holder.

? 9. In a'heat-exchanger, in combination, heat transmitting sheet metal bent to. a spiralshape to form spiral channels for the heat-exchanging media, a metal strip bent to a corresponding spiral shape adapted to close one of said channels at the edges of the spiral, which are substantially at right angles to the axis thereof, and a holder for the windings or said spiral metal strip, said windings being secured to said holder.

10. In a heat-exchanger, incombination, heat transmitting sheet metal bent to a spiral shape to form spiral channels for the heat-exchanging media, and at least one metal strip bent to a corresponding spiral shape adapted to close one of a said channels at the edges of the spiral which are substantially at right angles to the axis thereof, ,the windings of said spiral metal strip being directly secured to eachother.

11. In a heat-exchanger, in combination, heat transmitting sheet metal bent to a spiral shape to form spiral channels for the heat-exchanging 'media, a metal strip bent to a'corresponding spiral shape adapted to close oneof said chap nels at the edges or the spiral, which are sub- 'stantially at right angles to theaxis thereof, and

radial arms detachably secured to. said .heat-exchanger and adapted tohold the windings of said spiral metal strip.

12. In a heat-exchanging apparatus, in combination, a metal plate bent to form spiral channels, inlets to and outlets from said channels, and a removable spiral metal strip pressed in between these edges of said channel walls which are, substantially at right. angles to the .axis or said spirals.- v

' having such cross-section that the surfaces of said metal plate'arekept at a determined distance from each other.

nation, a metal plate bent to form spiral channels, inlets to and outlets from said channels, and

a spiral metal strip removably pressed in between those edges of said channel walls which are substantially at right ,angles to the axis of said spirals, the part or} said metalstrip inserted benation, at least one-metal plate bent to form,

tween the edges of, said metal plate having a sub.-

stantially rectangular. cross-section to keep the surfaces or said metal plate at a pre-determined distance from each other.

15. In a heat-exchangingjapparatus, in comit bination, metal plates cut to form spiral'channels for the heat-exch ging media, inlets to and outlets fromsaid channels, a spiral metal strip of said channel walls which are substantialb at right angles to the axis'ot said spirals, and another'metal-strip rolled centrally in said apparatus between said metal plates, said spiral metal strip and'said; other metal strip holding said 'metal plates at adetermined distance fromeach' other. v I

. r'emovably'pushed in axially between those edges 10 1 14. In a heat-exchan g apparatus, in combi- 

